Assessment Of Articular Fragment Displacement In Acetabular Fractures: A Comparison Of Computerized Tomography And Plain Radiographs

Objectives Quantitatively evaluate plain radiographs,relative to computed tomography (CT) scans, for assessment of articularfragment displacement (step and gap) in displaced acetabular fractures.Methods Retrospective evaluation of a consecutive series of CT scans and plain radiographs of 64 patients with displaced acetabular fractures in our hospital from January 1998 to May 2003. 20 patients met the inclusion criteria. Utilizing blind technique, Three independent reviewers measured step and gap deformity on plain radiographs and CT scans utilizing a standardized measurement technique. Sensitivity and specificity of plain radiographs for detecting step and gap displacement (2 mm and 4 mm) relative to CT scans were determined. Meanwhile, Intraclass correlation coefficient and intraobserver reliability was also calculated. Results compared to CT, plain radiographs showed poor sensitivity at detecting step deformity (sensitivity = 44.3%). When analyzed by fracture type, plain radiographs were particularly poor at detecting step deformities in fractures involving a single column of the acetabulum (sensitivity = 0%). Excellent intraobserver and intraclass reliability existed among the three reviewers. Conclusions â‘  Plain radiographs showed poor sensitivity for the detection of step and gap deformities in patients with acetabular fractures relative to CT scans; â‘¡ plain radiographs were particularly poor at detecting step deformities; and â‘¢ therefore,CT scans are essential and should continue to be used in conjunction with plain radiographs in the preoperative evaluation of displaced acetabular fractures and perhaps should be considered in the postoperative assessment of fracture reduction and predicting future outcome with regards to acetabular fractures.